If it were a windows program, I would use Auto it to automate testing. Is there something similar for browser-based apps?

Nothing too complex, it should just allow scripting (preferable for me to macro-recording) to simulate human interaction with the browser, which means being able to identify fields of a form by name, inject text into some, simulate mouse-click on others, etc and then, after submitting a form, should be able to read text certain named controls, check the status of others (checked, radio group index, read-only, etc).

While I do appreciate a full featured product, I don't appreciate a steep learning curve. so something as simple as the scripting of Auto It woudl be fine.

I don't know if it makes a difference which browser is used, but I could live with MSIE 6 or higher (maybe 7 or higher at a push).